1. Field
The invention relates generally to communication devices and systems. More specifically, the invention relates to increasing the signal-to-noise ratio (SNR) in retroreflector optical communication devices and systems over long distances.
2. Related Art
A prior art optical communication system may have a light source, a modulating retro-reflector and a detector. For optical communications, the light source emits light at a certain wavelength towards the modulating retro-reflector, which reflects the light back to the detector. One drawback of the prior art optical communication system is that the area (e.g., background) surrounding the modulating retro-reflector reflects the light producing stray light (i.e., noise) to the detector. Furthermore, the detector can receive other forms of noise such as background reflections and ambient solar radiation. The noise affects the signal-to-noise ratio (SNR), which is important in order to allow the detector to accurately and efficiently receive the information transmitted from the retro-reflector. Thus, a need exists in the art for an improved optical communication system and related method.